Background: Furans are global ecotoxicants making up the xenobiotic profile. High carcinogenicity and mutagenicity of these chemicals for humans even at concentrations as low as 10–12–10–15 g/kg, can pose health risks for the present and future generations.
Our objective was to develop and validate the authors’ method of measuring potentially dangerous furan and methylfuran in human blood to ensure control over the levels of exogenous compounds in biological fluids for further assessment of related human health risks.
Materials and methods: Development of the technique of measuring in human blood levels of furan and methylfuran was based on the following principles: establishment of gas chromatography-mass spectrometry (GC-MS) analytical conditions; experimental search for effective methods of blood sample preparation for the GC-MS analysis, and validation of the developed procedure.
Results: The method includes liquid-liquid extraction with a polar organic solvent in an alkaline medium during 5 minutes until the inter-phase equilibrium is reached and further capillary gas chromatography. It ensures a high degree of recovery of furan and methylfuran from blood samples equaling 98 % and 98.5 %, respectively. Mass spectrometry detection with registering the mass spectrum of ions was used for identifying furans in the biological fluid.
Conclusions: We have developed and validated a highly sensitive and specific method for GC-MS measurement of furan and methylfuran in human blood within the range of 0.0019 to 0.09 mg/dm3. The limits of detection of the chemicals were established within method validation, which appeared to be up to 0.00011 μg/cm3 for furan and up to 0.000021 μg/cm3 for methylfuran.

Introduction: Perceived air quality and satisfaction with it are significant components of the subjective quality of life in the population of modern cities that affect self-rated well-being and overall life satisfaction.
Objective: Theoretical validation of the construct “satisfaction with ambient air quality” that includes the subjective importance of air quality, its perceived quality and acceptability, and its testing within an empirical research in a Russian industrial city.
Materials and methods: In March 2023, we conducted a qualitative sociological research that consisted of 17 guided interviews with residents of Novosibirsk aged 18 and older. Text analysis was carried out using axial coding.
Results: The analysis of the interviews showed that the structural elements of the theoretical construct of satisfaction are present in everyday consciousness, especially when informants describe the quality of ambient air in their city. Yet, the elements were found to be often mixed and replaced with one another. The categories of “relevance” and “acceptability” were difficult to understand. The respondents could be divided into three groups: 1) those who unambiguously characterize the urban air quality, 2) those who refuse to talk about the city as a whole, focusing on more and less polluted areas, and 3) those who describe the quality of ambient air in Novosibirsk by comparing it with other Russian cities. We noted an adverse effect of ambient air quality on physical and mental health of the residents. Sources of air pollution were defined by the respondents in a fairly general way, e.g. “industrial enterprises”, “landfills, household activities”. Some talked about the advantages of living in the city, which compensate for air pollution. The informants often focused on discussing ways to improve air quality, which can be a marker of community outrage.
Conclusion: It is easier for the population to talk about ambient air by interpreting its condition. Most respondents agree that the air quality in their place of residence is rather poor. Overall, the perceived air quality and satisfaction are intersecting but not identical constructs. Negative perception of air quality does not necessarily mean dissatisfaction, especially in the presence of compensating factors.

Introduction: Lead oxide nanoparticles are generated during high-temperature processes at metallurgical plants and emitted in the atmosphere, thus posing high risks of human inhalation exposures. Despite a well-known toxic effect of lead and its nano-sized compounds on the nervous, hematopoietic, urinary, and reproductive systems, data on specific features of an acute inhalation exposure to its nanoparticles are still scarce.
Objective: To conduct an experimental study of acute toxicity induced by inhalation exposure to lead oxide nanoparticles in rats.
Materials and methods: The experiment was carried out on outbred female rats with the body weight of 247.9 ± 10.5 g divided into two (exposure and control) groups of 10 animals each. A single inhalation exposure to lead oxide nanoparticles (PbO NPs) at the concentration of 0.215 mg/m3 lasted four hours. The nanoparticle shape was spherical with a mean diameter of 18.2 ± 4.2 nm. Blood was taken from the tail vein of the rats to assess its hematologic parameters while the bronchoalveolar lavage fluid (BALF) was obtained to establish its cytological and biochemical characteristics 24 hours after the exposure.
Results: After the single inhalation exposure to PbO NPs, the results of the complete blood count showed an increased granulocyte count and a compensatory increase in erythropoiesis manifested by a significant growth of the reticulocyte percentage. The BALF analysis demonstrated that the exposure induced a pronounced cellular reaction in the lower airways accompanied by an increase in the neutrophil count and the neutrophil to alveolar macrophage ratio, which is an indicator of the cytotoxic effect of PbO NPs.
Conclusion: Inhalation exposure to PbO NPs at the experimental dose causes both general toxic and cytotoxic effects. The foregoing justifies the necessity of further studies aimed at establishing a no-effect concentration for lead oxide nanoparticles.

Introduction: The widespread use of vanadium in the metallurgical industry leads to its high content in the workplace air, which poses a threat to human health both in the workforce and the community. Vanadium accumulates in many organs and has a toxic effect; yet, studies of its effects on the thyroid gland are scarce and narrowly focused. This study is aimed at establishing the effect of vanadium on the functioning of the thyroid gland.
Objective: To establish thyroid status in rats after a single intraperitoneal injection of sodium metavanadate.
Materials and methods: Twenty-six male Wistar rats aged 3 months weighing more than 200 g were divided into a control group (10 animals) exposed to distilled water and two exposure groups (V11 and V18) of eight animals each intraperitoneally exposed to 11 and 18 mg of sodium metavanadate per kg of body weight, respectively. Serum levels of the thyroid-stimulating hormone, total and free thyroxine and triiodothyronine were determined by enzyme immunoassay.
Results: We observed that the high single exposure dose of sodium metavanadate caused significant changes in thyroid hormone levels. Administration of sodium metavanadate at the dose of 11 mg/kg b.w. induced an increase in the levels of total and free thyroxine but a decrease in the ratio of total triiodothyronine to total thyroxine compared with the controls. Administration of a higher dose of the compound (18 mg/kg b.w.) increased the levels of free triiodothyronine, free thyroxine, the ratio of free triiodothyronine to total triiodothyronine, and the ratio of free thyroxine to total thyroxine compared with the controls. We also noted the differences in health effects between the exposure groups, such as a higher level of free triiodothyronine and higher ratios of free triiodothyronine to total triiodothyronine and of free thyroxine to total thyroxine in the V11 exposure group.
Conclusions: Our findings show that a single intraperitoneal injection of sodium metavanadate at high doses of 11 and 18 mg/kg b.w. suppresses thyroid function and induces hypothyroidism, even 14 days after administration.

Introduction: Changes in the composition of surface water caused by hydrological and climatic processes and anthropogenic effluents affect its properties, making it potentially hazardous to human health. Monitoring of water quality and safety does not take into account all potentially dangerous elements and their compounds the man can be exposed to, since the occurrence of new substances and recombination of existing ones is accompanied by a continuous transformation of the physicochemical composition of water, which determines its biological properties. This screening study opens new perspectives for biological testing on cell cultures as an approach to assessing water safety.
Objective: To examine the method of bioassay of general indicators of water using rat fibroblasts and a regression model.
Materials and methods: We tested physicochemical parameters of water of a surface drinking water source sampled in fall 2020 and winter–summer 2021 and assessed its safety on rat fibroblast cells using the MTT assay. We then built a regression model of the cellular response based on 20 indicators, with the choice of the most significant predictors.
Results: We revealed seasonal fluctuations in the physicochemical composition of surface water with no toxicity limits exceeded. The lowest values of dehydrogenase activity of the fibroblast cell culture were revealed following the exposure to water sampled in autumn while that taken in summer had the most favorable effect on cell viability.
Conclusions: We revealed changes in physicochemical indicators characterizing quality and safety of source water in different seasons. Testing of the method of water bioassay (MTT assay) on the culture of rat fibroblast cells showed sensitivity in relation to general indicators of water quality. Based on mathematical modeling, we established that dissolved iron, which can serve as an indicator of changes in metabolic processes, is a parameter that reliably characterizes toxic effects on the fibroblast cell culture.

Introduction: A rapid growth of cities accompanied by the increase in population density and expansion of the road network has been observed recently. When conducting road traffic noise studies, preparation for observations, analysis of the situation, and selection of observation points are of great importance. Speed, volume, and density of the traffic flow, periods of observation, and the measurement interval are taken into account when measuring. At present, there is a need to justify approaches to organizing observations of noise levels and obtaining objective data on the urban territory.
Objective: To justify approaches to organizing observations of noise levels in urban residential areas.
Materials and methods: Roadway noise was measured on the territory of residential areas to establish equivalent and maximum sound levels. Organization of observations consisted of making a list of control addresses and distributing them by groups of observations with the same and comparable values of indicators.
Results: The work was carried out in accordance with the proposed approach to organizing observations with the list of control addresses generated, the addresses grouped, parameter values determined, and the control points selected. The essential parameters included the type of urban development, the type of green spaces, characteristics of traffic flow and road surface. Each group contained at least three control addresses. At each address, average sound levels were determined and control was carried out for their differences in each observation group.
Conclusion: Approaches to organizing observations of noise levels in urban areas have been developed, which help establish real-life acoustic conditions with a reduced number of measurements.

Introduction: The spread of selenium nanoparticles (Se NPs) increases risks of environmental pollution and human exposure, either accidental or following a targeted use of the products known to contain them, making the assessment of potential hazards of Se NPs particularly relevant.
Objective: To examine published data for subsequent assessment of potential hazards of selenium nanoparticles as a risk factor in both occupational and environmental settings at different levels of organization of living things.
Materials and methods: We have analyzed the results of studies published in 2001–2022 in English and Russian languages and found in PubMed, Google Scholar, eLibrary, CyberLeninka, and Scopus databases using the following keywords: selenium nanoparticles, toxicity, cytotoxicity, pathology, hazard, and risk. Forty-five original research articles were considered eligible for inclusion in the review out of more than 100 papers screened for information of interest.
Results: We have noted that health benefits of using Se NPs are discussed more frequently than their adverse effects. Yet, the ability of Se NPs to generate free radicals, exhibit a cytotoxic effect on tumor cells, and interact with proteins, although without changes in their secondary structure, has been established. Some authors also report acute and subacute toxicity of Se NPs observed, inter alia, in warm-blooded animals, as well as their accumulation in agricultural plants.
Conclusion: Additional in-depth studies of physicochemical, toxicological, and hygienic characteristics of selenium nanoparticles are necessary to specify the extent of their potential hazard for living things.

Introduction: Air pollution with nanoparticles (NPs) of different chemical composition is registered almost everywhere and, along with the growing use of nanotechnology products, poses serious human health risks related to NP exposure, included those for the nervous system.
Objective: To compare changes in functioning of the central nervous system in rats following subchronic intraperitoneal exposure to nickel, manganese, copper, zinc, lead, silicon, and titanium oxide nanoparticles based on the results of behavioral tests.
Materials and methods: We compared findings of our own subchronic toxicity studies of Ni, Mn, Cu, Zn, Pb, Si, and Ti oxide nanoparticles with a focus on behavioural responses.
Results: The comparison showed differences in severity of rat behavioral responses observed after subchronic intraperitoneal instillation of metal oxide nanoparticles at a single dose of 2.5 mg/kg of body weight. We observed a decrease in exploratory activity of rats that was statistically significant in the group of rodents exposed to Mn3O4, NiO, and PbO NPs, and a change in the summation threshold index that increased statistically in the CuO and ZnO nanoparticle exposure groups.
Conclusion: Our findings contribute to understanding of neurotoxic effects of nanoparticles and facilitate a more profound and trustworthy assessment of human health risks.

Introduction: Natural focal and zoonotic diseases are widespread in the Asia-Pacific Region, including Vietnam, due to climatic conditions, peculiarities of cultural and economic interactions.
Objective: To determine groups of population at risk of rodent and their ectoparasites-borne diseases in different landscape and socio-economic areas of Vietnam.
Materials and methods: We conducted a questionnaire-based survey of 449 rural residents from eight provinces in the north and central part of the Socialist Republic of Vietnam. The answers were analyzed using statistical and epidemiological methods.
Results: We have established that 346 respondents (77.1 %) come into contact with rodents, and five times more often this contact occurs in residential premises. A small number of the respondents reports flea (2.9 %) and tick (7.6 %) attacks. Only 30.7 % of the respondents (n = 138) know that contact with rodents can lead to disease, 69.3 % (n = 311) have heard about it for the first time. At the same time, 69.7 % of residents carry out rat control activities using various means while 30.3 % do nothing in this respect. If signs of a disease appear, 81.7 % of the respondents report seeking medical care, 9.4 % do that rarely, and 8.9 % have never sought medical attention.
Conclusions: Given the abundance of the main carriers and vectors of natural focal diseases, frequent direct contact of people with potentially infected rodents, poor alertness and awareness of the population, there is a high risk of infestation in case of an epizooty in the surveyed provinces. The most effective and affordable preventive tool is a targeted community outreach program.